Telephone-exchange system.



W, H. MATTHIES.

TELEFHONE EXCHANGE SYSTEM.

`APPL|CAT0N FILED Nov. 4, 19m` Patented Nov. 30,y MI5.

@WMM/y -W. H. MAUHIES.

TELEPHONE EXCHANGE SYSTEM.; Y

APPLICATION magnum 4. i920. 'g

Patented N0?, 30, 1915.

W. H. MATTHIES. TELEPHONE ExCHAMGE SYSTEM, APPLICATxogLjfLgHQV g; fgm.

Patented Nov. 30, 1915.

1 SHEETS-SHEET 4.

by l l' w. H. MATTHIES. TELEPHfoNE EXCHANGE SYSTEM.

APPLICTION FILEU NOV. 4. 19\0.

W. H. VUHES. 'TELEPHONE EXCHANGE SYSTEM.

'APPucATxoH mes Nov-:4, 1910.-

my@ K mmm Soma v TSHEETS-SHEETE.

'w. H. MATTHIES.. TELEPHONE EXCHANGE SYSTEM. V APPLICATI'ON FILED Moy. 4. |910. 1,161,874, Patented Nov. 30, 1915.

1 sHEETs-SHET 7.

)fl/l. bym/anni unirsi) srArEs .infirmer caricia.

'WILLIAM HUGO MATTHIES, OF ANTWERP, BELGIUM, ASSGNOE TO 'WESTERN ELCTRIC COMPANY, GF NEW YORK, N. Y., A CORPCRA'IIQN F ILLINOIS. 'l

TELEPHONE-EXCHANGE SYSTEM.

Patenten nov. eo, 1915.

Application tiled November 4, 1910. Serial No. o.

To all whom it may concern.'

Be it known that l, WILLIAM HUGO MAT- T11ms,'citizen of the United States, residingl 15 mav'be controlled and accomplished speedily andwith precision. ,a

One' of the features of this invention ren sides inthe provision of circuits and apparatus whereby a connecting circuit may be switch to hunt for and make connection to the terminals of said circuit at the called or outgoing end thereof.

Another feature of the invention' resides in the arrangement of the finder switches in groups and the provision of group selecting means for causingv a switch of any desired group to make connection to the outgoin end of a connecting circuit.'

A still Jfurther' feature of this invention re- ,sides in the provision of sending devices at ithe central oiice which are arranged to he set by impulses transmitted from an outlying station to govern the operation of the group selecting means.

i further object of my invention is to provide a system comprising mechanical switching apparatus adapted to connect telephone lines and trunk lines and to interconnect the same, and in which such telephone lines or trunk lines are or may be, or a part of them are or may be, connected or arranged according to some other system than the decimal system of notation, means 45 whereby impulses sent from a primarv controller and designed to accomplish the connection of a desired line, which' impulses are arranged according to the decimal system of notation, may be in eect so modified or reoperationof the mechanical switching apparratiis maybe controlled togaccbmplish the desired connection speedilyand with absolute precision.

extended by causing an automatic finder arranged byv a secondary controller that the' switching apparatus may be simplified in construction, lessened in cost and'increasedf in eiiiciency without any loss whatever in the speed `or precision ci its operation and with a decrease in the amount of such apparatus necessary for use in a system of any given extent.

My invention is shown as applied to a full automatic telephone exchange system, but it should be understood that while it is particularly adapted to and has been found especially eiiicient in connection with full automatic systems, my invention is not conined to use in such systems, but mfiy be advantageously used in connection Winn any or all systems involving mechanical switching apparatus which must bev rapidly and accurately controlled.

have furthermore shown my invention in connection with mechanical switching apparatus of a particular form, but it will be apparent that it is not confined to use in connection with switching apparatus-of this type, hut may be used with anyi-switching apparatus of suitable or convenient structure and arrangement. Furthermore,while the mechanical switching apparatus in connec.

tion with which I have shown my invention 1s controlled according to what is known as the revertive impulse system of control, it.

must be understood that my invention is not limited to such system of control, but may, if desired, be used in connection with switching apparatus designed to be controlled by impulses received from the controlling apparatus, as will he hereinafter pointed out.

My invention also includes certain details of the construction and organization of the circuits and apparatus involved in my iniproved controlling system by which the foregoing results and operations, and other results and operations incidental to the proper and expeditious accomplishment of the interconnection of telephone lines and trunk lines in systems of the character indicated may be hestaccoinplished.

The accompanying drawings which illustrate the preferred form ot my invention show as portions thereof features which in themselves form no p art ,of my present intem of control in accordance with my invenf tion; the lines .which extend to the edge oi 'each sheet being continued on the neighboring sheets.` The proper arrangement yof the sheets for viewing, the system as a whole is made by ,placing Figs. 1, 2, 3 and 4 in line horizontally from left to rightrespectively, and placing F ig. 5' immediately below Fig. 2. Fig. 6 is a front view of one of the register senders or register controllers of the character adapted to be used' in my invent'ion and form a part of what is known as the secondary controller therein. Fig. 7 shows a modified torni of register sender.

Like parts are referred to by the same reference characters throughout the specification. e

Line finders-Apart of the apparatus involved in the preferred form of my invention and as shown in the drawings herein comprises a series of line linders such as are shown to the left of Fig. 2 on the upper part thereof, to the left of Fig. 3 on the upper partv thereof, to the left of Fig. et on the upperpart thereoil and in the right-hand upper corner of Fig. 5. These line finders may be of any usual or convenient construction, but each comprises preferably a set of three brushes adapted to be rotated to sweep over any desired and convenient number of sets of line terminals, each such set of terminals comprising three terminals, that is, two line terminals and a test terminal, such brushes being ldriven by a power magnet indicated, for example, in Fig. 2 as 259. This power magnet may cause the rotation of the brushes over the terminals in-any desired manner, but 4preferably operates to drive such brushes by means of an electromagnetic clutch, such Vas is well known to the art and therefore need not be further described. Furthermore, associated 'with each of these line finders is a nder holding magnet which. when it is denergized, is adapted to hold the finderbrushes in the .position to which they have been drivenasuch holding magnet operating by means of-a mechanical center, ing clutchft'fcenter the 'brushes' upon the terminalsr with' ywhich they havel come in contact, as isnt/ell' understood, or in any other desired o'prefeiredmanner. The operation of these line' finders will therefore be seen to be accomplished through the ene-rgization of the inder' rotary magnet as 259 and the finder hold energized ,parallel as shown. lVhen these magnets ar""energized the brushes will beinef-magnet as 260 which mav be I gin to rotate, sweeping over the contact terminals of the various sets of terminals which appear in the particular line 'finder until the denergization of the tinder rotary mag# net and the iinder holding magnet, when they will stop and the finder brushes will remain in contact with the terminals of the particular line with which they are connect. ed at this time until the subsequent energization of the linder rotary magnet and the finder holding magnet.4 It should be furthernoted'that for the purposes to he hereinafter described, the test brush of the respective line finders is made of elongated form so that it will make contact with the test terminal of one set of' terminals before breaking contact with the test terminal of the p'reced-` y lng set. The line brushes, however, will not bridge from one line terminal to the next.

Sequence swtchea-The local controlling circuits associated with the various parts of theexchange system disclosed herein, which l local controlling circuits must be established in' definite order at successive 'stages of the 1 operation of such system to bring into service the different devices or parts as they are required, are in the present embodiment of .my invention established by automatic electromechanical switching appliances which are termed sequence switches. As will be noted by reference to the drawing, there is a sequence switch 201 associated with the primary finder apparatus, a sequence switch 501 associated ywith the secondary controller apparatus,a sequence switch' 301 associated asequence switch 4501 associated with the final finder apparatus and its associated selector. Each of these sequence switches con# sists in its elements of a movable switch op erating member, a number of c1rcu1t changers or contact devices actuated 1n sequence.4

- as said member is moved from'one position to another, an electromagnet' and a lnotor mechanism operated or controlled by said ber through its successive positions.

The sequence switch may control any desired sequence of operations, whether of the same or different devices. In each position to which this movable member is advanced,

' a circuit is establishedv whereby a given \op tion', in which position a new operation or .A another stage of the same operation w1ll be brought about and so on. quence'swltch establishes a condltion Where- Finallythe se#l i 10o with the intermediate finder apparatus and 110 magnet for advancing said movable .mem- 1 such position, the apparatus and its assofciated sequence switch may be and are preferably so related ythat local reciprocal conf trolling' circuits will be progressively estzblished by said devices in their operation, in such a manner that when a normal opera- -ffton of either 'is started both devices will be yprogressively carried through a complete cycle of operations which may be controlled and checked at dierent stages through the agency of energizing circuits established by some other portion of the apparatus for this purpose, but which unless so checked willterminate in the automatic return ot both the .sequence switch audits associated appaat'us to normal condition. In case of a failure of current in such checking or controlling goircnit,V even immediately after a sequence switch and its associated apparatus have rstarted in operation, such sequence switch and apparatus cannot become permanently displaced or stalled in an off normal condition but willr complete their cycle of operations and be positively returnedito normal under control of circuits which are 3o. purely local. I

In the circuit diagram 'herein illustrating y my invention, the switch springs ot the sequeuce switchesare not shown in their actual arrangement, but are so located as to give the clearest arrangement of circuits. 'Furthermorepthe operating cams are not shown. The positions of the rotary. element of each sequence switch, in which any of its contacts are closed, are indicated by numbers placed adjacent to such contacts, each contact, except the special contacts which will be hereinafter referred to, being open in all positions except those indicated by the adjacent numbers; For convenience, the sequence switch contacts may be identified with their sequence switch power apparatus, indicated uponthe diagrammatic showing, bythekf-act' that the hundreds digit of the reference; character applied to each sequence switch contact is the same as the hundreds digit of the reference character applied tov the sequence switch of which it forms a part. It will furthermore be observed .that the sequence switch contacts on any sheet. are all controlled and V,operated by. -thesequence switch power apparatus shown upon th`esame sheet; for example, all sequence'switch contacts the hundreds digitof whosefreference character is 2,-.form a part ofthe.

which arerepresented' by the contacts 202,

302, 402 and 502 of the respective sequence switches 201, 301,401 and 501 upon the drawings are closed only while the rotary element of the sequence switch is in transit from one stopping position to'the next, the numbers are placed on thc side of the switch lever opposite from the Contact and indicate the positions in which such contact is open, such contact being closed at all times while the rotary element is in transit between the positions indicated by thc numbers. ri'hus by reference to the numerals 1, 6, 8, 9, 10, 12, 14, 1G, 18, appearing adjacent to thc switch lever of thc special contact '202 of the sequence switch'201, it is seen that this-contactis open in the rst position of this sequence switch, closed continuously between the first and sixth positions, open in the sixth position, closed continuously between the sixth and eighth p0- sitions, open in the eighth position, closed between the eighth and ninth positions, open in the ninth position and so on. This contact being closed, for example, between the Y of the various sequence switches indicate therefore the only positions in which their associated sequence switches are adaptedto stop. Since, however, the sequence switches of the character described are known tothe art, the particular structure and arrangement of the form used and shown in the preferred form of my invention need not be particularly described and any form thereof whidch may be suitable or convenient may be use Wef paintA mkam'sm.-The wet poihtv mechanisms which are shown to the right of Figs. 2 and 3 partake somewhat of the nature of sequence switches. They compris\ each a rotatable spindle, the movement of which is adapted to be controlled by an electromechanical clutch, power being preferably supplied from a constantly rotating shaft precisely. as is the case in the sequence switches shown herein. Upon the eergization of the power magnet, therefore, the

spindle will' be rotated', such spindle carrying thereon means whereby the contact devices, shown immediately above the power magnet andportion of. ghspindle upon the drawings, will be operated, one set of said contact devices being operated in eachposition or stage of the rotation of the spindle and 'one-set only. Each set of contact devices comprises, as is plainly shown upon the d rawing, a test conductor terminal and va llocal conductor terminal.

Associated with the test, conductor terminal :is a normal ground connection and an alternate connection leading to sequence' switch contacts, and associated With the local conductor terminal is an alternate connection leading to other sequence switch contacts. lNhen, for example, the vvet point device spindle is in its firstposition after leaving its normal position, the ground connection will be removed from the test conductor terminal vE279 of the lirst group of contacts and the alternate terminal be connected therewith, and also the terminal 282 Will be connected with the local conductor terminal 297 of'the'same group of' contacts. When the Wet point device spindle by its further movement has reached its second position, the contacts of the first group havebeen restored to their normal condition andv the contacts of the second group are nonr operated and so on, there being as many groups oiV contact devices as may be desired. As soon. as the Wet point device'spindle moves out of itsrst position, moreover, there is a. contact 283 closed known-.as the ofi normal switch. llhis switch will be closed at all times except when the Wet point device spindle is in its normal position for purposes which will be hereinafter described. Furthermore, there is associated with each Wet point device an interruptor shown in Fig. 2 as 284, the contacts of which are adapted to be opened in the normal position of the yvve't point device spindle and in each ofthe positions in which the different sets or" Contact devicesy are operated by the spindle, but are closed at all times during the movement of such Wet point device spindle from one position to the next, for example, in its movement from its normal lvposition to its first position and in the movement from its first position to its second position and so on. Since, however, the particular structure of the wet point ,devices forms no part of my invention, it need not be further described, it only being necessary that 'the apparatus used in this particular connection performs the functions stated in asimilar or equivalent manner.

v Register senders-The register senders used inthe secondary controller forming a y'part of my invention may be of the form A clinedratchet teeth 7 8 and 79. .p -coiperate `with ,thel ratchet teeth 78 and 1n shown in Fig. G. vThis form of register 'A sender comprises a disk 7 6 rotatably mounted upon -a shaft 7T and having upon the periphery thereof tivo sets ot oppositely in dapted to such. coperation to drive the diskjin a clockwise direction, 1s the paWl SOmounted, as is clearly shown, upon the armature 8l f .of themagnetfSZ of which only the pole pieces areshown.l Co"perat1ng, on the other hand, with vthe ratchet teeth 79 and in such coperation adapted to drive the disk in a counter-clockwise direction, is the pavvl 83 by any unusual or external operation beyond shown various means 'nier-ere mounted, as is clearly shown, upon the armature 84 of a magnet 85 of which only the pole pieces are shown. Mounted upon the disk '76.is an insulatedstud 86 which, in the normal position ot the register disk forcesy the light spring 8T into contact With the contact spring S8 and out or" contact with the contact spring 89. When, however, the register disk 76 is moved from its normal position, the contact spring -87 vvill no longer make Contact with the spring S8 but will be in contactwith thev spring 89 and only be restored to contact with the spring 8S when the register disk is again fully in its nor mal position. There is also shown in this figure a friction brake 90 adapted, under the tension et the spring 91, to coiperate with the shaft 7? or a part carried thereon ain such manner that While the shaft and the supported disk Z6 may be rotated in either a clockwise or counter clockwise direction, it will st ay in any position to which it is driven, and in being driven to such position Will not overthrow or run by. This con;- struction, however, is so obvious and usual' that it need not be further described. 'l`heee is also shown in this register sender a brass stop plate 92 which by cooperation with the lng 93 prevents the movement of the disk 76 .what may be considered its normal limits. There also appears in the register sender such as springs, stops, etc., for controlling the proper operation of thepawls and armatures, but since the cooperation of these parts is so clearlyfshown upon the drawings and' is so Well knoivn to those skilled inthe art they.. need not be described'in detail. i. l It will be' obvious that upon the energization of the magnet 82, the armature 81 will be attracted and in the movementof s eh armature the pavvl will drive the regis er disk '(6 one step in aclockwise direction. This movement or" the register disk Willopen 11o the contacts 8? and 88 and 4close the contacts 87 ani-189, When the magnet 82 again 'is denergized and thearmature 8l is there-l by released the pawl 80 will be retracted preparatory .to a ,second operating movement 1]5 magnet, the armature 8l'-\vill be'afran at- 12ol i tracted and thepawl-SO will drive theregister disk in la 'clockwi sefdirectiona second step from Vits normal Aposition. That is to say, in response to 'each energi'zation oi Ithis magnet S2 the registe'rdisk 76 will bel driven 125 one step in a clockwise direction. This is the setting operation of the register disk. The register disk having been thus setgor adjusted the manner of its return to its normal position will be described. To accomplish this return, the magnet 85 will be operated thereby attracting the armature 84 which in its movement Will cause the pawl 83 to coperate with the teeth 79 of the register disk and in such coperation drive the disk in a counter-clockwise direction one step toward its normal position. Upon the denergization or"Y the magnet 85 the armature 8i and the pau'l 83 will he retracted and prepare themselves to drive the register disk 76 a second step in a counter-clockwise direction toward its normal position upon a subsequent energization of the magnet 85. It will be apparent, therefore, that with the particular arrangement of pawls and teeth shown, it Will require the same number of energizing impulses through the magnet 85 to restore the register disk to its normal positicn as passed through the magnet 'S2 to set the register disk in its set position. lVhen, therefore, the same number of energizing impulses have passed through the magnet 85 as have previously passed through the magnet 82, the register' disk 76 will again be in its normal position and the coni tacts 87, 89 Will be again opened and the contacts 87 and 88 be again closed. The detailed operation of these resister senders as applied to the system embodying m'y invention as shown herein will further ap- -pelar in the description of the operation of such` system.

The' modified form of register sender shown in Fig. 7, shows a register sender adapted for what is known as the direct system of control for mechanical switching apparatus rather than the rerertire impulse System of control, to which form of control theregister sender shown in Fig. 6 is particularly adapted, and the form shown in Fig. 7 furthermore indicates a register sender constructed and arranged to embody, when use d as a part of a system, what is known as translation. That is to say, impulses received which energize the magnet 82 will set the register disk 76 in precisely the same manner as in the register sender Shown in Fig. 6, but after the register disk has been set, instead ot' requiring the receipt of 'impulses of the same number as were received over the magnet- 82 to restore the register, disk, such register disk may he mechanically coupled hv 'any preferred means and at any desired time to the con stantly rotating shaft 98 shown in dotted lines on Fig. 7, and will send out or transmit impulses in its return to normal driven by such shaft, such impulses being. if desired, of a different or translated number or arrangement from those received by the register.

In the form shown in Fig. 7 the register disk 76 is provided on the portion opposite the ratchet teeth 78 with projections 99, which projections are of dieren't number to drive it in a counterclockwise direct-iony toward its normal position. The attraction of this armature 95 has also moved the contact device comprising the springs 96, 97 carried thereon into such position that the projections 99 in the return movement of theregister disk will come in contact with' the spring 96 and force it into contact with the spring 97 once foreach tooth 99 that passes thereunder. it will therefore be seen that the operation of the register disk to any desired or predetermined set position by current impulses passing through the magnet 82 will result, when the magnet '94: is energized, in a distinct and predetermined number'of circuit closures between contacts 96 and 97. It will therefore be further apparent that a register sender of the -form shown in Fig. 7 is particularly adapted for controlling the operation of automatic switching apparatus of the form in which impulses are sent from the sender to the automatic switching apparatus to drive the same intothe desired posi-tion, and furthermore that such form of register sender is particularly adapted for use in systems Where the impulses received from What may be called' the primary controller, must be translated before they are transmitted to the automatic switching apparatusvwhich they are designed to control.

Primary c0n7'0ZZer.-The`primary conf troller vforming a part of the system embodying my invention shown herein and which is located at the subscribers station upon a calling line, may be of any desired structure or arrangement which will perform thev desired functions. The preferred form, however, which form is Well known to the art and Will therefore n ot be described in detail, comprises a switch 171, a switch 172, a switch 173, and a resistance 174. The switch 171 in its normal position closes through the contact devices 17o-and 17 6 the circuit of the line conductorA 106 of the calling line., In its operated position, however, the switch 171 closes that portion of the line conductor 106 leading to the subscribers substation apparatus directly to ground.

' ladapted to entirely oren the circuit. and the' this ground connection the switch 172 is connection :["rointhe portion of this donduca plurality of wellv each of which ls'adapted set to indicate, when taken tor leadintj to the central oliice Ato ground through the switch 172and furthermovement thereof lwill supply power forV the peration ofthe. Various digits dials in their movement to their normal position. Each of these dials "in their return to their norbrush carrying1 mal posit n, in which movement the dials will mo'4L et'jneafter another, will close the switch 173 'according to the number to which the dial was set and' then open once 4the switch 172. That i'slto say, it the first dial is set to the number 5 and having ldoneso'l will open the switch 172 once. Assumingthat the next dial was .set to the number it will then operate and close the switch 17 3 so will open the switch 172 once, and so forth. flies each of the dials has been restored tonormal and in its restoration to normal operated the switches 172 and 173` as required, the switch 171 will be again closed and the operation of the troller will he completed. The detailed op eration of this primary controller so far as is necessary for an understanding of my invention will further appear in the general description of the operation of the 'system of 'which it forms a part.

elector mechanism. -`With particular reference to the selector mechanism as shown in Fig. 4, it comprises a switch carriage or member of the rotary type, the frame 21 oi`wl1ich is mounted upon a central standard or shaft 22. t the outer end of the frame a number Qt sets of contact brushes Q3, F24- upon but insulated from a rod and from each other, in position to sweep over sets of line terminals Q7, 28, 29. -The brushes have inwardly extending arms 30, bearing against which, one for each brush, are springs 3l. Latches B2, one for each set of three brushes', are pivotally' mounted upon a yrod u arranged normally being rocked outwardly vinto line with the stationaryterminals. Bearing against the inner'ends'of the latches are springs 34 comprises in addition to thev the designation' of the desired line.

a power lever, the first movement it will close, in its return movement, the switch 173 six times,

primary con-.

, 25 are nivotallv mounted i l n f y33 'and' toholdthe brushes from l which hold the latches firmly against a stop rod 36. This stop rod 36 serves to prevent' the latches from being moved forward too far after the. brushes have been released. A stop bar 35 serves to limit the outward movement of the brushes when the latches are withdrawn. rlihe latches 32 and stop bar 35 are A circuits connected with the brushes will noti be crossed thereby. The springs 31 make;y

electrical connection lWiththe brushes; they are oi sheet metal and form the teeth' of combs 'which connect corresponding brushes in ie '-everal sets in multiple. Suitable wire clipterminals 37,88 and 39 are provided for the circuit connections to the springs and brushes.

^ As the brush thebrushes'to sweep over the fixed terminals, the latches rst pass by a tripping device or brush selector, by w of insulating material so that the i carriage is lrotated to cause.' I

n l y nch any desired 'set of brushes may be released and caused to twice, and haring done leased swing outwardly. This tripping device comprises a shaft 40 provided with radially extending lingers '-11 arranged spirally about the surface of the shaft. This shaft Ais adapted by mechanism, to be presentlydescribed, to be rotated so. as to bring' the fingers one after another into the-line of tra-'rel o1 the several latches on the brush carriage. Only one set of brushes is intended'to be released in a given operation. They shaft 40, therefore, is first rotated Vto bring? a particular finger into position to. engage the latch in the same level therewith andV then the brush carriage is rotated. ln .pass ing, the outward edge oi' this latch' strikes the end of the finger, allowing one set of three brushes to berelease l. Continued moiv'ement or the brush carriage brings the the rows of stationary terminals in the icyel therewith, these brushes trailing in passing. The brush carriage is finally` caused to stop with the selectedbrushes in contact with some one minals. The other brushes, lnot being re' mina .s over which they pass A further" are held out of contact with the 'ter-A 115 movement or the brush. carriage in tlie'sam' selected set of brushes into engagement with' same over the terminals and making contact therewith f set of stationary terv direction of rotation will carry the bsushesj over a restoring' roller pix'oted to the frame free ends of the released set, causing them', to be pushed back into their normal latched positi n. After making a full revolution, tbe br ish carriage is brought to 'restjin its. normal position again.' l 'W' Y In the normal position of the brush carria ge, as shown in Fig. 4, a pair of. levers 42, 43 engage at their free ends a plate 46. roller 71 which and ais-thc 69. which may be .mi-iever i8 is e normalstopflV .Y AAt the end of the lever si?, is. ai' lies in a recess of plate 46,3 "l

rightV aegis.

and which engages the A izo able force against plate 46 and thereby holds' the brush carriage securely in its normal position. A Hat spring 52\engages an inwardly extending arm 45 of the lever. 43

and serves to press this lever outwardly 'but with less force than that of the coil spring 54. The spring 52 also makes electrical contact with lever 43; it is secured to butinsulated from the shaft 22 ot the brush carriage and terminates in a Wire clip 53.

As the brush carriage is moved to carry the brushes over the stationary terminals, the-roller 7l and the extension arm 72 engage the teeth of a cam plate 50. The roller 71 rides over Vthe teeth While the brushes are passing between terminals and drops into a notch as any1 released set of brushes is 'centrally located in a direct contact With a set ot terminals. The extension arm 'T2 follows behind the roller one tooth or notch and likewise engages a tooth as the brushes are passing between successive terminals. It passes through the space between teeth, however. wit-hout touching the plate 50, as the released set. ot brushes is centrally located in 'contactwith the ez-minnie. The stop bar 35 engages the inwardly extending arm 45 just as `it does the arms 30 ot' the brushes and thus prevents the extension arm 72 of the lever 43 from touching the bottom of the notches between the teeth of plate 50. but permitting said arm 72 to touch and malteV contact with the top 4of the teeth.' The teeth and notches of plate are so spaced and arranged with respect to .thecontact lever 43 that the extension arm 72 will not break contact-With a toot-h .of plate 50 until after the brushes malte contact with the stationary terminals and the roller 7l is ready to drop into anoteb. The circuit arrangement, as willpresently appear. is such that tlie'motire nower for driving the brush carriagecannot be cut o until the contact is thus broken between lever 43 and plate 5,0

and -therefore not-until the `brushes are in f positionto make good contactwith'the stationaryjterminals. The brush selector is also .provided with an interruptor or make andbreak-contact .device comprising an afin 56 pivoted to the` traine 57., engaging at tact may be ot the ordinary spring character,the free end only ofwhich is shown in the drawing. In the normal position of the vshaft-40, the arm 56 lies in a notch of the disk 58.50 that the arm 56 is out' of contact -With the s ring contact 59, as' clearly shown upon the, rowing, When the shaft is away There are as many teeth von-the cam asA there driving roller 64.

vroller e.

from its normal position, the arm 56 maires intermittent contact with the spring Contactv 59, this contact being made when the arm 56 is shifted by each tooth on the cam 58.

are tingers 41 on the shaft 40 and therefore as many `as, there are sets of brushes, each; space between two' teeth-.upon theicam 58l corresponding to one of the Lfingers 41 and` its coperating set of brushes. When, there:

fore, the arm 56 rests in the space between any tivo teeth on the cam 58, a certain oneeof the fingers 4l is in operative position to re# lease its cooperating set of brushes as Will the drawing.

The motor mechanism :tor causing the ro tation of the'hrush carriage comprisesan annular iron friction dish 61 flexibly mounted at the lower end ot the shaft 22, an electromagnet 62 which may be affixed in any suitable manner to the frame and a constantly rotating shat't 63 carrying an iron The disk 61,' roller-'64, and that part of the shat which extends through the center ot' theelectromagnet 62 form the magnetic circuit-,of the ,electro-v magnet 62. When, therefore', current. is passed through the Winding-of this-magnet, the roller 64 attracts the disk S1- and causes the latter to rotatel by .trictionalbontact therewith. T he power shaft 63 is extended as shown in the drawing to carry aiierrilolyV mounted driving disk which is adapted to engage a roller 6T carried by the spindle 40. An electromagnet 68 controlsvthe engagement of the disk 70 and the roller` 67 in the same manner that theelectromagnet 62 controls the engagement of Adisk 61 and magnetic clutches, onetocnnse the movement ot' the brush carriage and. the other to cause the movement of the brush selectors.

The complete selector skvimh mechanism is not shown in the diau'ing,brit"the elements thereof appear inl their properrelation to one another so as tomalte clear the .manner in which the mechanism foperates tojinterconnect lines. There may be as 'many sets ot brushes and stationary terminals as deisired. For example, the switchmechanism shown herein being a hundred point selector, f may and preferably will ha-ve as a'vwhole tensets of three brushes eaehfand one hundredsets of fixed terminalsarranged in ten levels'of ten sets each; For simplicity,Y in the diagram there are only 'showntwo 'sets of. brushes-the'cighth and ninth counting from the top down, and sixsets of stationary terminals in two levels corresponding to the two sets of brushes shown. Slt will oe obvrious that 'the number and arrangement of brushes .and terminals may be changed or modifiedas may be required in 'any partienlar installation.'

These devices are'int'aetelectrocuit is now established from the battery 101 through the subscribers line relay 102, contact '103 oi the cutoff relay 104, line conductor 105, the substation apparatus and the' now closed switch hook 151line conductor 106, contacts 175 and 176, armature 107, and its back contact of the tone relay 108, ground relay 109 to ground and back to battery. This circuit, by the energization of the relays 102 and 109, places battery,

Athrough the front contact of the relay 102,

uponthe test Wire 110 individual to the calliijtghnef and ground, through the front contact or the relay 109, upon the .local Wire 111 indiVi'dualVto the group of 'primary' line in every Wire 111, front brush 258 of thisV primary line finder.

finders, in ivhioh group of inders the terminals of the calling line appear.

Immediately that ground is placed upon the local Wire 111 a circuit is completed from battery through the primary finder line relay 251,sequence switch contact 203 of the primary finder sequence switch 201', local contact and armature of the relay 109 to a ground and back to battery. A circuit similar to this circuit will be closed one'of the idle primary line finders of this particular' group. Since, however, the vsubsequent operations of all these line nders will be the same until one of the line iinders seizes the calling line, the description to that point will be only 01"' the opera tion ofthe line finder which does actually seize the calling line.

Upon the energization of the primary finder line relay 251, a circuit will be established from battery through the armature 252 and its front contact of the line relay 251, armature 253 and its back contact of the primary intermediate relay 261, se.

guance switch contact 201, left winding or". the primary hunting relay to ground and back to batry. The closure of `this o "cuit energies the relay 255 which attracts its armatures. A substitute circuit is new closed for the energization of this relay 255, such .circuit being traced from battery through the armature 252 and its front contact of the relay 251, right winding of the relay 255, front contact and armature 256 of such relay and conductor 257, 'tothe test Sc 'longen the brushes of this finder are in contact with the terminals oi? @xn-idler orgy-tion# line numbered 5149, the

theline finder over bu 'disturb br affect any oallingline, this circuit Will be completed to ground and back to battery either through the armature112 and its back contact of the relay 102, through the armature 1111 and its front contact of the relay 108, the operation i of which will be hereinafter described, or through the test brush of some already oonnected primary finder. That is to say, thev hunting relay 255 will be maintained energized by this circuit so long as the line relay 102 is not energized and the vtest brush 258 rests upon the test conductor vot an idle or non-calling line, It should be further notedthat the testr brush 258 of the line finder is made in extended or. elongated form, so that when passing from one test terminal to the next, contact is made by it with each test terminal before it isbroken with the preceding one. The energization of the relay 255 has alsoclosed a circuitv for the finder rotating magnet -259 and vthe finder holding magnet 260 which may be traced from battery through such` rotating and holding magnets in parallel',l left Wind-v ing of the primary intermediate relay 261, sequence switch contact 205, front contact A and armature 262 or' the relay 255, to ground and back to battery. This circuit moreover energi'zes the inte'rmediate.'relay 261 which attracts its armatures and thereupon a opens at` the back contact of its armature 253 the origin'al energizing circuit through' the left Winding of the relay 255. .It Will be noted that now the energization of the hunting relay 255 depends wholly upon the fact that the test brush 258 of this finder rests on the test terminal of an idle or non-callingy line.

Before proceeding further it Will be noted 1 that the intermediate relay 261, by its energization,-has closed for itself a second or locking circuit which may be traced vfrom battery through'the armature 252 and its front Contact of the relay 251, `armature 253` vand its front dontact of the relay 261, vthrough vthe right Winding of such relay,

sequence switch back to battery.

The finder rotating magnet i259 and 4the iinder holding magnet 260 being energized, the rotation of the brushes 263, 26.4, 258 will begin, such brushes passing over the vterminals of the various lines terminating in this particular group of `line finders.. The brushes 263 and 264 passing over the terminais of idle or non-calling lines will in no way disturb the electrical character or condition of such lines since the conductors 265 and 266 connected to such brushes are. not connected to either ground or battery at any`125 points at this stage of the operation of the primary line nder apparatus. It Will therefore be apparent that the movement'of' f lines will in no Way".l

conversation whichv 'U0 contact 206 to ground andmay be taking place over such lines. When, howewer, thetest brush 25,8 reaches the test i retract its armatures. vThe'"circuit Vof the nder rotatingg magnet 259 '7110"1'3.l 'ing magnet 260 of thisjilierinediac'e line finder will 'thereorebe immediately :opened therelay 255, and the 'mogenientftofthe minals of thecalling line.

At the same time that te fuif 255 bijna denergization opened thecircuit of the finder rotating magnet 259, it'cl'osedfa circuit,"i n-` cluding the primary .selectijlg frelayh@ from battery 113 through the'front contanti and armature 112 of the subscrihers lineV relay 102, right winding of, 'relay 104, back contact and armature'll of vthe tone relay 108, testl conductor 110; test brush f ture`268 and fronticontacto'f the'relay 251 Y toz .258 of the primary nder, armature 256 'and its-back `contact of the relay' 255', sequence Switch contact 207, :winding'of `the selecting relay 267, sequence switch contact l208, armato ground and back to battery.. It this primary finder is the only one which'atthis time has its brushes in contact withfhe terminals of the particular line, which we have assumed to be calling, the relay 267 will be energized. If, however, any other primary finder should at this time have its brushes connected to the terminals of this particular line, the selecting relays 267 of the two finders will be connected in parallell andinsuicient current will be supplied from the battery 113 to energizeeither-- one of these selectinfil relaysA We will assume, however,

Aat vpresent that but oneline .finder is now connected to the terminals of this line. andv will defer until.laterthdy consideration ci the opertions which ill tempted simultaneous seizure of the line by two primary finders. This selectingrelay 267 will thereupon attract lits-armature.

At the same time that t e circuit wasestalished for theselecting relay 267 'bythe' armature "256 of the now forthe primary .sequence switch 201which the lprimary line -inder sequence switch 201,

sequence switch Contact 209, front contactA and armature 270 of the relayf261, vback contact andarmature 262 of the relay 255 to ground and back to battery. The primary finder sequence switch 201 will now move and under the control of its special contact 202 will vcontinue to move until it reaches the sixth position. -While `the primary tiene# follow the ntenergized relay '255,43 circuitwas established by theretraction of the armature 262 of such'relay 255 l finder `sequence switch is passing through its Y secondi-to fthv positions it maintains 'through the sequence switch contacts 208 and 201 fthe circuit for the selecting relay* ,gizedto prevent.. the closure of a circuit through its 'back contact for purposes which 'j willbefghereinafter described, but also mainj ,gtainsaj'ground upon the testbr`ush258'and at the front vContact 'o f thearmature 2624zof 'therethrough upon the test conductor of the 'callin line'which renders this line idlev vor Abrushes Vof thisinder will th"erinlx'nij cea'se" with such brushes in f ntact;with the non-.calling to au of the ether, prmaryne "fnderiniwhch itappears.. i' .f *Thgprhnaryvnder sequence switch in outof its first position opens the se-` lquene switch contact 209, breaking the origiener king circuit of the sequence Vswitch itselfanr opens at the sequence switch1con cts 204 and 205 the original energizing cir- `cults of thorelay 255 and the relay 261 re- 'j spectively. The sequence switch in this movementhas also opened the sequence` jswitc-hv contact 210 and in its 'third andourth'posi'tions 'closed the sequence switch contact y quence switch contacts 210 and 211y is withv"The operation of these seand vthis relay is thereupon denergized.

The sequence switch furthermore on coming into .its fifth position` closes vthe sequence switch contact 212. Thlis'places through the whichhas been` above: described. This. .1o not onlyma'intains the selecting relay ener-' I resistance' 285 a lground uponthe test ter- -minalof the calling line independent of'v the sequence'switch contacts 207 and 208 and l malntai'ns the test terminal ofthis line' so Vthat it will test busy or non-calling to the i brushes fof the vother primary line inders'in which this line appears. Asthe sequence yswitch leaves its fifth position it opens the sequence switch contacts 207 and208, but since the sequence switch Contact 212 has already been closed and the sequence'switch contact2l1 has already been opened, the .ope-ning of these sequence switch contacts .andfthe consequent.denergization of the re- 'Upon coming into its sixth position the primary finder sequence. switchv closes vthe se- 'quence switch contacts 213,` 214,"215,`i216, 2175218 and219.

The closure offthescquence switlf-contacts '216 'and' '217' has clcsed[a1circnrtrfrom-battery through the "sequence'switch contact216, sequence switch contact -211-,flsuneryisory line relay 272,1ine conductorQGL 'b1-usl1f26i, line conductor 105,

Vsubstation pparatus-l. line conductor icsgspgteii `.171,11are conductor 196, back ,lzcontact andgarmatnre 10'; of the tone relay 4. vwill come to rest only wheniitreaches of the relay 555 for' the secondary controller sequence switch may be traced as follows.; battery, through the secondary controller neq uence switch 501, sequence switch 'Contact 501, armature 554,- land front contact oftherelay 552, back contact and 'the relav 555 to te The secon ary controller sequence 15., lswitch will n ow move from its first position, ",lnd under fthe control of its'special vcontact tez sixth position. yIn this movemenbthe' ,frequence switch hasopened' the contact "503 mfbut befQr pening'such contact hslclosedl; switchcontact 506, in this man;`

"-ner su' itutingA for' the 'circult of the 'test 1 relay 558 the ground connected to its own sfrmature in place of the ground connected toithelarmature 538 of the relay 551. --It vwill sixteenth position of the secondary v con-v troller sequenceswitchjis passed, the test :relsy 5 58gwill beT rnafintain edv energised'so long'af'sibatte issuppled thereto over the ,""The line-V relay .551 being eneifiged byi theopening ofthe sesiyitch` .contact 503 has opened the -jfcircilit ith'rough theleft vwinding ofthe .intermediate relay 552 and suchrelay wills-lao he denergized. f

:g Whileftfhe sequence switch 501'is moving lr'rougliftsfourth and -fifthpositions av cir- 1 cuitgisftemporarily closed extending from m' thfojigh the primary finder sequence tchf 'tact 216, vselecting relay 267, sev'switch contact .218, terminal 27 4secndary controller finder brush" 542, secondary controller, sequence switch 4contact 5 09, :front contact andvarmature ofthe relay 558 tofground andiback to battery. This temgorary circuit. 'energizes the selecting relay v tiTMhich-attracts its ,armature and closes a .circuitfo the primary 'nder sequence v:Soyswitch@driving itvr under -thecontrol of its specialcontact 202, from its sixth position into its. ei lith position, l The circuit may .be traced roinbattery through the primary finder sequencexswitch 201, sequence switch contact` 219, front contact andv armature of v theselecting relay 2,67 to ground and back toliattery. 1 i he 'primary finder sequence switch in passing out of. its sixth position has opened opening the circuit for the secondary controllerline relays of all ofthe unsuccess- .ful secondary-controllers, which thereupon .cease their movement.- It will be remem- 8,5 vberel'that theline finders of all of theA idle;- lay 527, resistance 526,?bac'k contact and nrarmature- 5575.1? round and back to batand thereafter until thesixt .the sequence switch contact 213, thereby secondary controllers of this group began ,to move upony the closure of the "tindex-'sequence switch contact 213, and that with the exception of. the secondary" c ontroller line finder'which has seized the .ter-

primary minals of the calling primary .tn'der,`.

the idle secondary controllers of this 'group have continued in their movement. l/Vhen,

.fhoweven the primary finder sequenceswitch contact -213 opens, the line Yfinders of all such idle secondary controllers will stopand Vaw it the subsequent closing of the primary 'n r sequence'switch contact 213 of this particular primaryfinder, or of some'other primary finder of "the'group with which theyare associated. The primary Ender se- 'ilkfquen'ce switch in moving into its' seventh and ghth 'positions has, by means ofthe seuence switch contacts 212, 220 and 221, cut

fout'the resistance 285 between the test brush ,258 of theyprimary line finder and ground,

" so that inthe seventh and eighth positions Y enth position Ais passed, it is connected .directly r toground j first through the' 'sequence switch contact "bnnoted thatfrom this time on until they 221 and thentlirough the sequence 'switch contact 220,' thefeircuit throughthe sequence v switch contact221 being closed before the I'sequence switch contact 212 is opened. The

" nected directly to. earthwithout eitherthe resistance ofthe, relay '267 or the resistance 285, suilicient current will pass to energize lthe cut-off relay 104, which thereupon attracts its armatures closing by its armature '115 and .the front contact thereof a shiit including resistance 118 around the front contact andl armature 114 of the relay 108, and alsoby its armature 103 openingl the .circuit btweenI the subscribers line relay 102 and he lin conductor 105,'at. the Same time providing a substitute path to ground for said isubscribers line relay and thereby maintaining it energized through such armature 103, its front' contact and the ilo resistance 121. It should benoted at this point that current is now ,supplied to the ground relay 109 from battery through the sequence switch contact 215, superyisory line relay 272, line conductor 266, line conductor 105, substation apparatus 152 and line' conductor 106. A The primary finder sequence switch being now in its eighth position' and the secondary controller sequence switch being now in its sixth position, the operation of the primary controller apparatus 170- located at the subscribers station, the controlling-circuit being closed up to thetront contactof the armature 107 of the tone relay 108 as follows battery, secoridary controller sequence switch 511,'register switchingrelay 528,.register operating ethe apparatus is `readyy for A mature 5,96 of the units trnsferreiay' 597-1,

5149. If' the subscriber has followed these instructions, the primary line finder and the secondary controller will have associated themselves' Withhis lineA before the sendingoperation of thev primary controller begins.

To accomplish this the movement of the finder brushes in the respective line finders `and their associated sequence switches vare adapted to bel accomplished,y if necessary, vathigh speed Without loss in accuracy and precision. If,ihowever, for ,any-'reasom either' through vthe yneglect of instructions by the subscriber or by the holding up of any of the operations of the primary finder or secondaryycontroller, the opera-tion of the primary controller should beginbefore the primary finder and secondary controller become associated with the subscribers line, certain operations take placeto prevent confusion, which operations will be hereinafter rreferred to. ,-It will be assumed for the present that the primary finder and the secondary controller have become. associated with the 'calling line before the switches of the primary controller, indicated at 171, 172

40 and'173, begin their operations.I

' When now vthe Aswitch 171 is operated a ground will be placed upon the back contact 17 5 thereof before the circuit is opened by the "movement of the movable member 176 of such vswitch and its closure with the-front contact thereof.; This ground onythe back contact 175 of this switch maintains vthe energizing circuit of the .Supervisory line relay 272, which circuit therefore, continues to depend upon theclosed lcdndition of the cause the energization of thesivitchginiz y're-#115 subscribers switch hook. lIhe operation of :lav `-J25j but theregister settingrelay'527' E 1""- the switch 171 of the primary-controller has,.ivill not be" operated owing to the inclusion" however, caused the deneitgization of the cf the resistance 174. `lVhen, howeverpthe'w f" ground relay 109', which thereupon, retracts lirst or thousands dial in its Voperation* closes its armatureand completes a circuit; for the the Switch 173, thereby shuntingwthejre- '120 c tone relay 108,v suchvcircuit being traced sistance'l'fhthe registersetting relay' 52'71- f-r' from battery through the front contact and iwill be energized attracting its armature and v` armature of the 'subscribersline relay 102,v clbsing f the' fdllowing circuit z-ffromfbatrelay 108, back 'Contact and armature ofthe Vtery througlrthe thisands registering mmgj-V f f relay 109 to' ground and back to battery. net 562, baclrcontat'andarmature 56.6"of'12517 f The tone relay is thereupon/energized and 'the thousands transferv relay 564,-fro'nt coni iii-attracting its armature 107 extends theY Itact and farinature cf the registering seti' controlling circuit, heretofore traced to the ting relay 527 to ground and back to bats front contact thereof, through-such varmatery. The closure' of this circuit causes ture 107, line conductor 106, movable mem= manera adjusted. as to indicate the designationof c' per 17e of hamaca infeilfeemiiaere lcontroller, front Contact thereof, switch 172,' I, resistance -lYetto ground and back to lhatterj/.f f V u. f l. -ffs It maybe noted that atthisgtime, aswilzl' ',70 be hereinafter lpointed out, the movement ofL '1.

yall unsuccessful line finders will cease' .due'- to ythe denergization of( thegroundi-relay 109as just described, provided, of,course,-'f"f that there are no othercalling linesin'tliis group which as yet no priinz'iry finder hat- 3 successfully seized Gf course,. Y' .is .maintained on local Wire aint ythis time bly an energiaed ground ,relay ofsoine" other callingline of'this grou-p, vthe-Vuile280 successfullI 'primary line iinder'sfwillnot* stop,

primary controller may be ,as desired ofnanyy i construction' anc 'arrangement well `l'nown to the art, in which'dials. or efpiivalent'dea.4 'i' vices are provided which may be-vsoset or '90' the desired line, and Awhich, aftei'fhzi-tingg" been set 'or adjusted, maybe cahsedjtonso 7 operate Athat they will one.. `after ,another close the-switch 173 responding* tothe nuin'oeiwdesignated suchV dial, and before the operation of next ysucceeding; dialonce. openitlrje sw 172;' In the preferred form, afterthe dit have been `setor adjusted .towinclicate tf di@ designation of the desiredline,.tlieirppen ation is started and controlled'by :the in'ovef'- ment of' a lever, in movement ,of ,which-1 lover the switch 171 is operated, :such-svfitcliey f 171 remaining operated `until thecomple-"i05- tion of the'operation of allof, the fdials or equivalent devices ofthe primary,cont-roller.. l' The dials ofthe primary controller have' y ing been yset to indicate the designation-of'- the desired line/in the and the switch 'heretofore traced Opellhfl, the Circuit; thmughvth@ primary con-Ev troller and the relays 527 andQSrisxcomlf f y :Thislwi-ll' pletcd through the', resi-stance 174,

the thousands register magnet to be enerM but if thisis'the only line calling at'Y 'j' `this time, the movement.I of these unsuccess- "-1 a number of tim-05,60%. e5;

case, assumed, 5149', 110:

nieuwe* gized and to voperate jpawl associated therewith to drive the dlk of the thousands register 561 clockwise one' step from its normal position.,y When the switch i173 fis again opened atthe primary controllerfthe regis-l ter setting relay 527. will'be again denergized-and by the, opening of the circuit, heretofore; traced,fthe thousands "register magnet will lalso beV denergized, and will thereupon be ready upon a second closure of its 'energizing circuit to control its associated l pawl insuch a manner as to move the disk of the thousandsregister 561 a second step; It willv be noted, however, 'that the disk of this thousands register 561 in its first step hasopened the contacts 568 and closed the contacts 563. This has prepared a circuit which'may be traced from battery through .,thevcontacts 563, left winding of the theli sandstransfer relay 564, sequence switch contacts i505 to the hack contact `of the switching. relay 528, which relay, however,

it willbe remembered, is now maintained en- In the case assumed the thousands digit of the designation of the desiredeline was. 5. The switch L73 will therefore be operated Six times by the thousands dial of. the

primary controller, and, 'through the oper-f ation of the register setting relay 527 six" times in response to the closure of this' switch 173, the thousands'register magnet has moved the register disl: of the vthousands register six steps. At this time the switch 172 of the primary'controller will be operated once. This by opening the circuit lntir'ely will'cause the denergization of the switching relay 528 and the circuit, heretofore traced throughthe,left winding of the thousands transfer relay 564, willl be completed, energizing such thousands transfer relay 564. This thousands transfer re- Y lay by the attraction of its armatures has.

I closed for itself a locking circuit from battery through the right-hand winding of such relay, front contact and armature 565 vof such relay, sequence switch contact 507 to ground and back to battery. The primary function, however, of this relay was to transfer the control of the register setting relay 527 from the thousands register magnet to the hundreds register magnet, and it did this by the attraction of its armature 5,66, so

that now a circuit may be traced fr ornbat-Y tery through the hundreds register magnet 572, back contact and armature 576 of thehundreds transfer relay 574. front contact andarmature 566 of the thousands transfer Vrelay 564 to the front contact of the register setting relay527. Before the hundreds dial or equivalent devicerbegins to move in' 'the primary controllerv the switch 172 is again closed, energizing the switching relay 528 and opening the original circuit to the i thousands transfer relay 564ea Thehundreds" dit; 'in

itsmdwifent, since it was set toA designate the figure 1 will close the switch 173 twice l and: then j cpen the switch 172 once. 1t may here be notedthat 1n the operation ofeach of'the dials,vf it is set to the 0 digit, it will close the; switch 173 once inv its operation in returning to normal; if it is set at l it will operate theswitch 173 twice; if it is set at 2vitwill operate the switch 173. three times, etc. ;l that is to say lthat ifthe thousands dial, for example, is 'set at theaiigure Q it means that the line desired is located in the first thousands group of lines, at the exchange and therefore a` single im;v pulse will be sent by closing the switch 173 in'- order toselect at the proper time the .first thousands grou The operation of) of lines at the exchange., the 'hundreds dial thereforev has caused the register setting relay 5,27 to pull .up and releasetwice, thereby closingl through its armature to -ground the circuit which has been heretofore traced from the hundreds register magnet 572, which circuit y has energized such magnet to cause the disk of the hundreds register 571 to advance clockwise two steps from'its normal posi-` tion.' As so'ox'i as thev huhdredsregister left` its normal position the contacts`r578 were opened and the contacts 573 Were closed, preparing a circuit from battery' through the contacts 573, left winding of the hundreds transfer relay 574,7sequence switch contact 505, and back contact of the switching relay 528. Whenv now the switch .172 is opened once vby the movement of the hundreds dial, the switching relay 528 will be denergized and in retracting its armature complete the circuit through the left wind-J ing of the hundreds transfer relay 574, which has just been traced.v This will cause the energization of` the relay 574 which.

closes a vlocking circuit for 'itself through its 'armature575 and its front contact and the sequenceswitch contact 507 similar tof the locking circuit of the thousands transfer relay, and also shiftsthe control circuit of wellfunderstood causing it to move five steps from normal in response to the' live'v closures ofthe switch 173therebyouten1ng the contacts randzclosing the conta 'it 583 'saA ,the register setting relay from the hundreds 

